Trump, continuing to build his Cabinet as he prepares to take office on Jan. 20, said Oklahoma Attorney General Scott Pruitt, 48, would be nominated to head the Environmental Protection Agency. Pruitt sued the EPA in a bid to undo a key regulation under outgoing President Barack Obama that would curb greenhouse gas emissions blamed for climate change, mainly from coal-fired power plants.
Trump tapped retired Marine Corps General John Kelly, 66, for secretary of the Department of Homeland Security, whose responsibilities include immigration. Kelly, the third retired general named by Trump to a senior administration post, last year told Congress that a lack of security on the U.S.-Mexican border posed a threat to the United States.
Trump's transition team said Republican Iowa Governor Terry Branstad, 70, who has boasted of close ties to Beijing's leaders, was picked as U.S. ambassador to China.
In addition, transition officials said Linda McMahon, 68, former CEO of professional wrestling company WWE and wife of wrestling kingpin Vince McMahon, was Trump's choice to head the Small Business Administration. Trump has taken part in WWE events in the past and has close ties to the McMahons. He is a member of the WWE Hall of Fame.
All four posts require Senate confirmation.
Pruitt's selection came despite a softer tone Trump has struck on environmental regulation since his Nov. 8 election. He has stepped back from casting climate change as a hoax, signalled he might be willing to allow the United States to continue participating in the Paris climate change deal aimed at lowering world carbon emissions, and met with former Vice President Al Gore, a leading environmental voice.
Pruitt's selection brought a quick rebuke from Democrats.
"The head of the EPA cannot be a stenographer for the lobbyists of polluters and Big Oil," House of Representatives Democratic leader Nancy Pelosi said of Pruitt.
Trump's campaign manager, Kellyanne Conway, brushed off the criticism, praising Pruitt's record and telling reporters at Trump Tower: "We're very accustomed to the naysayers and the critics."
Trump talked tough during the campaign about deporting all of the estimated 11 million illegal immigrants in the United States and building a wall along the Mexican border. But since the election he has softened his comments on deportation and referred to some illegal immigrants as "terrific people."
Kelly would work in tandem with Republican Senator Jeff Sessions, Trump's pick for attorney general, who is a leading advocate of cracking down on illegal immigration.
He formerly headed the Southern Command, responsible for U.S. military activities and relationships in Latin America and the Caribbean. He was a proponent of keeping open the U.S. military prison in Guantanamo Bay, Cuba.
Trump previously picked retired Marine Corps General James Mattis as defence secretary and retired Army Lieutenant General Michael Flynn as national security adviser.
Branstad has been an eager trading partner with China, helping Iowa sell agricultural goods to the Asian powerhouse. His choice came after Trump rattled the world's second-largest economy with tough talk on trade and a telephone call with the leader of Taiwan.
Trump has more key appointments to make in coming days, including the high-profile job of secretary of state. His team said former Republican presidential candidate Mitt Romney, a fierce Trump critic during the campaign, is still under consideration for a diplomatic job.
Aside from the personnel announcements, Trump basked in being named Time magazine's "person of the year," telling NBC's "Today" show, "It's a great honour, it means a lot."
In an interview with Time, Trump continued to take on corporate America, promising to bring down drug prices and causing shares of U.S. pharmaceutical and biotech companies to fall.
(Reporting by Richard Cowan; Additional reporting by Steve Holland, Warren Strobel, Valerie Volcovici and Timothy Gardner in Washington and Bill Berkrot, Lewis Krauskopf, Melissa Fares and David Ingram in New York; Editing by Will Dunham and Jonathan Oatis)